1. Field of the Invention
The present invention relates to a method of forming a trim cover assembly for an automotive seat, and more particularly relates to a method of welding a film of decorative pattern to a trim cover assembly by means of a high frequency.
2. Description of the Prior Art
To provide a decorative pattern on a trim cover assembly, there has been enforced a decorative film lamination method using a high-frequency welding.
FIG. 1 of the accompanying drawings illustrates a typical conventional method of this type. According to such method, a lower electrode (11) and a welding die made of silicone (12) are employed, and in particular, a cutting blade (16) is provided at the peripheral ends of the welding die (12). The process consists of the following steps:
(a) Placing an insulation paper (13) on the lower electrode (11),
(b) Laminating a film (15) on the insulation paper (13), the film (15) being adapted for pattern formation, and then a substrate (14) of synthetic resin leather or synthetic resin woven fabric, on the film (15), the substrate (14) referring to a trim cover assembly,
(c) Lowering the welding die (12) having an uneven welding surface (12a) and pressing it against the film (15), with the cutting blade (16) trimming the film (15) along the peripheral contour of the welding die (12).
It is therefore observed that the film (15) is cut into a certain decorative shape and given a certain uneven pattern in a simultaneous fashion, thus providing a decorative pattern on the substrate (14).
However, the above-mentioned method is found defective and disadvantageous in the undermentioned aspects
(1) In the case that a leather or a thin film is used for the substrate (14), it is highly possible that the cutting blade (16) will penetrate into such kind of substrate and cut the same unexpectedly, so that any kind of material can not be used for the substrate (14).
(2) In order to retain a sufficient cutting precision to cut the film (15) precisely, the welding die (12) per se, which has the cutting blade (16) thereon, must necessarily be formed and installed with a high precision, not to mention the blade (16).
(3) The cutting blade (16) requires a fine adjustment of its projecting status relative to the the welding die (12) according to a varied thickness of the film (15), thus involving a troublesome step.